A hydrofoil is a device designed to provide “lift” to watercraft such as surfboards, sailboats, and other watercraft. Generally, a hydrofoil comprises a wing-like structure connected to a watercraft via one or more struts. As a watercraft increases in speed, the flow of water across the foil generates lift which, in turn, raises the watercraft and results in increased speed and, for powered watercraft, a decrease in fuel expenditure.
The effectiveness of a hydrofoil depends, in part, on its design. As a general rule, the thickness and dimensions of a hydrofoil directly impact the effectiveness of the hydrofoil in providing lift. Additionally, the design of hydrofoils is impacted by the intended use of the hydrofoil. For example, in recreational uses, one must consider the safety of the participant when designing, for example, the strut length, to avoid potential injuries that may occur upon “wipeouts.”
While often used for powered watercraft, hydrofoils may be employed in a variety of watersports such as stand up paddle (“SUP”) surfing or SUP boarding. SUP surfing and SUP boarding are sports where SUP boarders or riders maintain an upright stance on their boards and use a paddle to propel themselves through the water. There are various modes of stand up paddling, including flat water paddling for outdoor recreation, fitness, or sightseeing, racing on lakes, large rivers and canals, surfing on ocean waves, paddling in river rapids (whitewater SUP), SUP Yoga, and even fishing.
Hydrofoils for watersports such as SUP surfing, regular prone surfing, or SUP boarding have previously been implemented but suffer from numerous drawbacks. Generally, most existing hydrofoil designs utilize a long strut length which can potentially can result in serious injury, especially for inexperienced riders. Additionally, most hydrofoils (for both watersports and powered vessels) utilize thin forward main lifting wings (in canard style foil setups it is the back wing as the main lifting wing) and have a symmetrical thickness across the chord length of the main lifting wing.